Anyone living in a house with a basement in the New Madrid Fault section of the US should install a methane detector.

Ehow on the explosion and detection of methane:

“Explosion: Methane is extremely flammable and will easily cause explosions. It can leak unnoticed into structures and spaces, and a tiny spark can ignite the undetected gas. Explosions from methane gas are extremely strong, and the damage is devastating. The explosions associated with methane gas are not limited to the space that has the highest concentration, but anywhere it has seeped. It may be in one room, or it can travel through an entire city block.

Detection: Like smoke detectors and carbon monoxide detectors, methane detectors are available to alert you when dangerous gases are present. The audible alarm is a safeguard against poisoning from the deadly gas and from explosions that can result from methane leaks.”